Mastodawn

Is it ethical to place a birdbath next to my berry patch with the intent of letting my cats get there predatory instincts out?

If you are in the US, deliberately hunting birds with an unsupervised pet cat is almost certainly a violation of the MBTA.

The Migratory Bird Treaty Act of 1918 (16 U.S.C. 703-712) implements four international conservation treaties that the U.S.

FWS.gov

Interesting. Thanks for this